#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ide.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/gpio.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <asm/mach/map.h>
#include <asm/uaccess.h>
#include <asm/io.h>

/**********************************************
Copyright @ tiny
file        :newchrled.c
author      :tiny
version     :1.0.0
description :led driver file
other       :none
log         :first version 2023-03-02
**********************************************/

#define     NEWCHRLED_CNT       1
#define     NEWCHRLED_NAME      "newchrled"

#define     LED_OFF             0
#define     LED_ON              1

/* led gpio register address */
#define     CCM_CCGR1_BASE              (0x20C406C)

#define     SW_MUX_GPIO5_IO03_BASE      (0x20E0028)
#define     SW_PAD_GPIO5_IO03_BASE      (0x20E02B4)

#define     GPIO5_DR_BASE               (0x20AC000)
#define     GPIO5_GDIR_BASE             (0x20AC004)

/* remap gpio register address */
static void __iomem *IMX6U_CCM_CCGR1;
static void __iomem *SW_MUX_GPIO5_IO03;
static void __iomem *SW_PAD_GPIO5_IO03;
static void __iomem *GPIO5_DR;
static void __iomem *GPIO5_GDIR;

/* newchrled device struct */
struct newchrled_dev{
    dev_t       devid;
    struct cdev cdev;
    struct class *class;
    struct device *device;
    int major;
    int minor;
};

struct newchrled_dev newchrled;

void led_switch(u8 sta)
{
    u32 val = 0;

    if(sta == LED_ON){
        val = readl(GPIO5_DR);
        val &= ~(1<<3);
        writel(val, GPIO5_DR);
    }else if(sta ==LED_OFF){
        val = readl(GPIO5_DR);
        val |= (1<<3);
        writel(val, GPIO5_DR);
    }    
}

static int led_open(struct inode *inode, struct file *filp)
{
    filp->private_data = &newchrled;
    return 0;
}

static ssize_t led_read(struct file *filp, char __user *buf,
                        size_t cnt, loff_t *offt)
{
    return 0;
}

static ssize_t led_write(struct file *filp, const char __user *buf,
                        size_t cnt, loff_t *offt)
{
    int retvalue;
    unsigned char databuf[1];
    unsigned char ledstat;

    retvalue = copy_from_user(databuf, buf, cnt);
    if(retvalue < 0){
        printk("kernel write failed!\n");
        return -1;
    }
    
    ledstat = databuf[0];

    if(ledstat == LED_ON){
        led_switch(LED_ON);
    }else if(ledstat == LED_OFF){
        led_switch(LED_OFF);
    }
    return 0;
}

static int led_release(struct inode *inode, struct file *filp)
{
    return 0;
}

/* device operation functions */
static struct file_operations newchrled_ops = {
    .owner = THIS_MODULE,
    .open = led_open,
    .read = led_read,
    .write = led_write,
    .release = led_release,
};

static int __init led_init(void)
{
    u32 val = 0;

    /* init led */
    /* 1.led gpio register remap */
    IMX6U_CCM_CCGR1 = ioremap(CCM_CCGR1_BASE, 4);
    SW_MUX_GPIO5_IO03 = ioremap(SW_MUX_GPIO5_IO03_BASE, 4);
    SW_PAD_GPIO5_IO03 = ioremap(SW_PAD_GPIO5_IO03_BASE, 4);
    GPIO5_DR = ioremap(GPIO5_DR_BASE, 4);
    GPIO5_GDIR = ioremap(GPIO5_GDIR_BASE, 4);

    /* 2.enable gpio5 clock */
    val = readl(IMX6U_CCM_CCGR1);
    val &= ~(3<<30);
    val |= (3<<30);
    writel(val, IMX6U_CCM_CCGR1);

    /* 3.set gpio5_io03 mux function */
    /* set gpio5_io03 pad */
    writel(5, SW_MUX_GPIO5_IO03);

    /* set gpip5_io03 pad attr */
    writel(0x10b0, SW_PAD_GPIO5_IO03);

    /* 4.set gpio5_io03 as output pin */
    val = readl(GPIO5_GDIR);
    val &= ~(1<<3);
    val |= (1<<3);
    writel(val, GPIO5_GDIR);

    /* 5.default set led off */
    val = readl(GPIO5_DR);
    val |= (1<<3);
    writel(val, GPIO5_DR);

    /*register chrdev driver */
    /* 1.alloc chrdev num */
    if(newchrled.major){
        newchrled.devid = MKDEV(newchrled.major, 0);
        register_chrdev_region(newchrled.devid, NEWCHRLED_CNT, NEWCHRLED_NAME);
    } else {
        alloc_chrdev_region(&newchrled.devid, 0, NEWCHRLED_CNT, NEWCHRLED_NAME);
        newchrled.major = MAJOR(newchrled.devid);
        newchrled.minor = MINOR(newchrled.devid);
    }
    printk("newchrled major=%d,minor=%d\n",newchrled.major, newchrled.minor);
    /* 2.init cdev */
    newchrled.cdev.owner = THIS_MODULE;
    cdev_init(&newchrled.cdev, &newchrled_ops);
    /* 3.add cdev */
    cdev_add(&newchrled.cdev, newchrled.devid, NEWCHRLED_CNT);    
    /* 4.create class */
    newchrled.class = class_create(THIS_MODULE, NEWCHRLED_NAME);
    if(IS_ERR(newchrled.class)){
        return PTR_ERR(newchrled.class);
    }
    /* 5.create device */
    newchrled.device = device_create(newchrled.class, NULL, newchrled.devid, NULL, NEWCHRLED_NAME);
    if(IS_ERR(newchrled.device)){
        return PTR_ERR(newchrled.device);
    }


    return 0;
}

static void __exit led_exit(void)
{
    /* unmap gpio register */
    iounmap(IMX6U_CCM_CCGR1);
    iounmap(SW_MUX_GPIO5_IO03);
    iounmap(SW_PAD_GPIO5_IO03);
    iounmap(GPIO5_DR);
    iounmap(GPIO5_GDIR);

    /* unregister chrdev */
    cdev_del(&newchrled.cdev); /*del cdev*/
    unregister_chrdev_region(newchrled.devid, NEWCHRLED_CNT);

    device_destroy(newchrled.class, newchrled.devid);
    class_destroy(newchrled.class);
}

module_init(led_init);
module_exit(led_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Tiny");